Fiber oxidation oven with multiple independently controllable heating systems

1. A method of heating fibers using an oven in which a chamber is formed, the method comprising:

heating gas using a first heating system located outside of the chamber;

heating gas using a second heating system located outside of the chamber;

supplying the heated gas from the first heating system into an upper portion of the chamber to heat fibers in the upper portion of the chamber at a first temperature; and

supplying the heated gas from the second heating system into a lower portion of the chamber to heat fibers in the lower portion of the chamber at a second temperature different than the first temperature such that the upper portion and the lower portion of the chamber maintain the different temperatures without a physical barrier between the upper portion and the lower portion of the chamber.

2. The method of claim 1 , further comprising:

directing the heated gas from the first heating system to a supply structure disposed between first and second ends of the chamber, wherein supplying the heated gas from the first heating system into the upper portion of the chamber comprises supplying, from the supply structure into the upper portion of the chamber, the heated gas from the first heating system; and

directing the heated gas from the second heating system to the supply structure, wherein supplying the heated gas from the second heating system into the lower portion of the chamber comprises supplying, from the supply structure into the lower portion of the chamber, the heated gas from the second heating system.

3. The method of claim 1 , wherein heating gas using the first heating system comprises heating gas using at least one heating element included in the first heating system; and

wherein heating gas using the second heating system comprises heating gas using at least one heating element included in the second heating system.

4. The method of claim 1 , further comprising:

receiving, using a first return structure positioned near the first end of the chamber, at least a portion of the heated gas directed into the chamber;

directing at least a portion of the heated gas received using the first return structure to a first return outlet formed in the chamber;

receiving, in the first heating system, at least a portion of the heated gas directed to the first return outlet;

receiving, using a second return structure positioned near the second end of the chamber, at least a portion of the heated gas directed into the chamber;

directing at least a portion of the heated gas received using the second return structure to a second return outlet formed in the chamber; and

receiving, in the second heating system, at least a portion of the heated gas directed to the second return outlet.

5. The method of claim 1 , wherein heating gas using the first heating system comprises heating gas using the first heating system to a first target temperature, and wherein heating gas using the second heating system comprises heating gas using the second heating system to a second target temperature, wherein the first target temperature differs from the second target temperature.

6. The method of claim 5 , wherein the first target temperature is higher than the second target temperature.

7. The method of claim 1 , wherein the oven comprises a center-to-ends oven;

wherein supplying the heated gas from the first heating system into the upper portion of the chamber comprises:

supplying the heated gas from the first heating system into the upper portion of the chamber from a center of the chamber towards opposite ends of the chamber; and

wherein supplying the heated gas from the second heating system into the lower portion of the chamber comprises:

supplying the heated gas from the second heating system into the lower portion of the chamber from the center of the chamber towards the opposite ends of the chamber.

8. The method of claim 7 ,

wherein supplying the heated gas from the first heating system into the upper portion of the chamber from the center of the chamber towards the opposite ends of the chamber comprises:

supplying the heated gas from the first heating system into the upper portion of the chamber from the center of the chamber towards the opposite ends of the chamber so that the heated gas from the first heating system flows parallel to a direction of travel of the fibers within the chamber; and

wherein supplying the heated gas from the second heating system into the lower portion of the chamber from the center of the chamber towards the opposite ends of the chamber comprises:

supplying the heated gas from the second heating system into the lower portion of the chamber from the center of the chamber towards the opposite ends of the chamber so that the heated gas from the second heating system flows parallel to the direction of travel of the fibers within the chamber.

9. The method of claim 1 , wherein the method further comprises:

returning, to the first heating system using first ductwork, at least a portion of the heated gas directed into the chamber; and

returning, to the second heating system using second ductwork, at least a portion of the heated gas directed into the chamber;

wherein the first ductwork and the second ductwork are independent of each other.

10. A method of heating fibers using a center-to-ends oven in which a chamber is formed, the method comprising:

heating gas using a first heating system;

heating gas using a second heating system;

supplying the heated gas from the first heating system into an upper portion of the chamber from a center of the chamber towards opposite ends of the chamber to heat fibers in the upper portion of the chamber at a first temperature; and

supplying the heated gas from the second heating system into a lower portion of the chamber from the center of the chamber towards the opposite ends of the chamber to heat fibers in the lower portion of the chamber at a second temperature different than the first temperature such that the upper portion and the lower portion of the chamber maintain the different temperatures without a physical barrier between the upper portion and the lower portion of the chamber.

11. The method of claim 10 ,

wherein supplying the heated gas from the first heating system into the upper portion of the chamber from the center of the chamber towards the opposite ends of the chamber comprises:

supplying the heated gas from the first heating system into the upper portion of the chamber from the center of the chamber towards the opposite ends of the chamber so that the heated gas from the first heating system flows parallel to a direction of travel of the fibers within the chamber; and

wherein supplying the heated gas from the second heating system into the lower portion of the chamber from the center of the chamber towards the opposite ends of the chamber comprises:

supplying the heated gas from the second heating system into the lower portion of the chamber from the center of the chamber towards the opposite ends of the chamber so that the heated gas from the second heating system flows parallel to the direction of travel of the fibers within the chamber.

12. The method of claim 10 , wherein the first heating system and the second heating system are located outside of the chamber.

13. The method of claim 10 , wherein the method further comprises:

returning, to the first heating system using first ductwork, at least a portion of the heated gas directed into the chamber; and

returning, to the second heating system using second ductwork, at least a portion of the heated gas directed into the chamber;

wherein the first ductwork and the second ductwork are independent of each other.